Break at Control Points

[b_daddy]

Can I break a spline at any of the control points or create a spline from control point to control point?

[b_daddy]

bump

[Thad]

Does Create-Spline-Manual give you what you're looking for in order to create a spline from control point to control point? Create-Spline-Blended Spline works real nice for bridging a gap.

 

Thad

[Thad]

If you can get the control points to become actual entities, it would be easy to break the spline at any one of their locations. I don't know how to turn the control points into points.

 

Maybe you could zoom way in and break nearest? If that meets your tolerance requirements.

 

Thad

[b_daddy]

Thanks Thad,

 

I guess I was figuring that seeing how MC was recognizing the control points that it might be able to break at them or even trim to them. I ended up doing what you had suggested and broke them at the nearest.

 

Thanks for the help

[Thad]

[Roger Peterson]

create - point - node points

[Thad]

Roger,

 

I tried that this morning and got points off into space. I know what they do, but I thought that Bryon needed points on his spline.

 

Thad

[b_daddy]

Roger,

 

That did acomplish what I was after.

Thanks

 

 

Thad,

I wanted to break the spline at one of the control points, which by creating points nodes as Roger suggested, I was then able to break the spline to the points.

 

Thanks again for the help guys

[Thad]

Here's the sample that I tried.

 

 

 

Although 2 are close, the end points are the only ones that are on the spline. I didn't think that would do you much good. Perhaps a spline with less drastic changes would've come out nicer.

 

Glad to you got it.

 

Thad

[Colin Gilchrist]

Hi Thad,

 

The reason your points lie off the spline is that your spline is NURBS. A NURBS (Non-Uniform, Rational, Bezier Spline for the uninitiated) Spline is created by a set of control points which lie off the spline and pull the spline in the direction of the control points. To get points which lie on the spline you must have a Parametric spline, which is defined by a set of points which lie directly on the spline itself. To create a Parametric spline, go into the System Configuration and select the CAD Settings page. Change the "Spline/surface creation type" to Parametric.

 

Now use the Create Curves Spline function to create a new Parametric spline from the NURBS spline. Go to Create, Spline, Create Curves Spline. Select the spline(s) you want to convert using the chaining dialog box. Press ok to close the chaining dialog box. On the ribbon bar set your tolerance to .0001 and press the apply button. You should now have a set of Parametric splines. Create, Point, Node points will now give you points on the spline.

 

Hope that helps,

 

Colin Gilchrist

IRC NC Programming

The Boeing Company

[Thad]

quote:

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Hope that helps

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Yes it does. Thanks Colin!

 

Thad

[Colin Gilchrist]

Thad, You are very welcome!

 

Bryon,

 

The other thing to be aware of is that when you are breaking your splines, Mastercam will create a "trimmed spline", that is, a spline of the original length that is now trimmed to a point. The problem is that it can change the end condition of the spline at the end point (trim point) when you are driving a toolpath. Use the WholeSpline Chook to create a new shorter spline(s).

 

From the Mastercam help file:

 

 

WholeSpline C-Hook:

Use this C-Hook to convert a trimmed spline to a whole spline. When you trim a spline, Mastercam simply truncates the displayed spline but internally retains the original shape. If you choose to extend a trimmed spline, it will follow its original path. After using this C-Hook, the trimmed portions of the spline are discarded. If you later choose to extend the spline, it will not follow the original path since that information is no longer available.

 

Thanks,

 

Colin Gilchrist

IRC NC Programming

Mastercam Focal

www.boeing.com